A compressor includes: a rotation shaft which is allowed to rotate around an axis; an impeller which is configured to pressure-feed a fluid from one side in an axial direction toward an outside in a radial direction by rotating together with the rotation shaft; a casing surrounding the rotation shaft and the impeller and in which an exit flow path guiding the fluid pressure-fed from the impeller is formed; and an acoustic liner which is installed to face an inside of the exit flow path in the casing. The acoustic liner includes: an acoustic space which is formed inside the acoustic liner; an introduction hole communicating the acoustic space with the exit flow path; and a vortex suppressor which is placed in a connection area between the introduction hole and the acoustic space and is configured to suppress vortexes which occur in the connection area.

An acoustic device comprising an enclosure having an enclosure wall that defines an enclosure volume; a first mass movably coupled to the enclosure, the first mass comprising a sound radiating surface, a voice coil and a first suspension member; a second mass movably coupled to the enclosure, the second mass comprising a magnet assembly and a second suspension member, and wherein the first suspension member couples the first mass to the second mass, the second suspension member couples the magnet assembly to the enclosure wall, and the second suspension member is tuned to reduce enclosure vibrations caused by a movement of the first mass and the second mass relative to the enclosure.

A headset having a talk-through microphones incorporates an audio circuit that disconnects or compresses a signal representing sounds detected by the talk-through microphones in response to the audio circuit detecting the onset of a peak in the signal that exceeds a predetermined voltage level, and that does so with a rate of change in voltage level that exceeds a predetermined rate of change in voltage level. The duration of the disconnection or compression may be controlled by a timing circuit set to a predetermined period of time that may be retriggerable while amidst the predetermined period of time.

In some examples, devices for detecting and measures a ghost echo current in an audio signal are described. For instance, the device may be configured to sample a current of an audio signal, compare with an expected current, and determine an impulse response of the ghost echo current based on the sampled current and the expected current. The device may also be configured to reduce the ghost echo current using the impulse response.

A method for detecting and mitigating parasitic oscillation in a headphone equipped with an active noise reduction (ANR) system. A fundamental frequency of a microphone signal is determined from a microphone of the ANR system and an amplitude of the determined fundamental frequency is compared to a threshold level to determine parasitic oscillation. If parasitic oscillation is determined, then the microphone signal is altered to mitigate the parasitic oscillation.

An earpiece (100) and acoustic management module (300) for in-ear canal echo suppression control suitable is provided. The earpiece can include an Ambient Sound Microphone (111) to capture ambient sound, an Ear Canal Receiver (125) to deliver audio content to an ear canal, an Ear Canal Microphone (123) configured to capture internal sound, and a processor (121) to generate a voice activity level (622) and suppress an echo of spoken voice in the electronic internal signal, and mix an electronic ambient signal with an electronic internal signal in a ratio dependent on the voice activity level and a background noise level to produce a mixed signal (323) that is delivered to the ear canal (131).

For protecting a speaker, an input signal is received, and an excursion of the speaker that would be caused by the input signal is predicted. In response to the predicted excursion exceeding a threshold, a targeted excursion of the speaker is determined by compressing the predicted excursion. The targeted excursion is translated into an output signal, which is output to the speaker.

A voice controlled assistant has a housing to hold one or more microphones, one or more speakers, and various computing components. The housing has an elongated cylindrical body extending along a center axis between a base end and a top end. The microphone(s) are mounted in the top end and the speaker(s) are mounted proximal to the base end. The microphone(s) and speaker(s) are coaxially aligned along the center axis. The speaker(s) are oriented to output sound directionally toward the base end and opposite to the microphone(s) in the top end. The sound may then be redirected in a radial outward direction from the center axis at the base end so that the sound is output symmetric to, and equidistance from, the microphone(s).

An apparatus including a microphone; a speaker including at least one vibrating element and at least one movable section, where the at least one vibrating element is configured to at least partially move the at least one movable section to generate sound waves from the at least one movable section; and at least one vibration dampening member between the microphone and the at least one movable section, where the at least one vibration dampening member is suitably positioned in a path of vibration transmission between the at least one vibrating element and the microphone, where the at least one vibration dampening member is configured to absorb vibrations when the movable section is actuated by the at least one vibrating element.

A multi-path audio amplification system that provides an output drive signal to electromechanical output transducers provides improved undistorted headroom, reduced path switching noise, and/or improved frequency response performance. Multiple signal amplification paths receive an audio input signal and have corresponding multiple output stages that have differing output impedances. A mode selector selects an active one of the multiple signal amplification paths is selected to supply the output drive signal. Outputs of the multiple output stages are coupled to the electromechanical transducer to provide the output drive signal and at least one of the multiple signal amplification paths includes an equalization filter for filtering the audio input signal to compensate for phase or gain differences referenced from the input to the outputs of the multiple output stages due to interaction between the differing output impedances and an impedance of the electromechanical transducer.